It is known to provide so-called Location Based Services (LBS) in cellular communication networks, such as a cellular wireless telephone network. Such services typically comprise a mechanism for estimating the location of a mobile terminal, e.g. with the help of a Global Positioning System (GPS, Galileo, Glonass) or a Mobile Positioning System (MPS) that may use Cell-ID information or algorithms based on timing advances and on triangulation for determining the position of a mobile terminal. Said LBS mechanisms are known to enable content delivery based on the location of the user (mobile terminal). Based on the knowledge of the mobile terminal's location, specific location based services can be offered to said mobile terminal, e.g. alert messages for upcoming road traffic hazards or indications toward deviations to avoid traffic jams.
The actual locations of the mobile terminals, or at least information indicating the respective locations, that the location based network services may rely upon are usually kept in some database being updated by means of location updates sent from the mobile terminals. Further, in order to be able to send specific information to these location based selected mobile terminals, there will be also an association of the location data to identification data of the respective mobile terminals, for example the respective telephone numbers for sending and addressing messages thereto.
However, such conventional concepts for providing localized network services in cellular communications networks employ a dedicated generation and retrieval of position data of the mobile terminals in that, for example, the mobile terminals have equipment for determining a location from satellite based services (GPS, Galileo, Glonass) and provide the network service provision side with this information so that the respective location database can be kept up-to-date. Alternatively, the network infrastructure may need to employ the aforementioned MPS to determine the terminals' locations and to update the location database.
Thus, the determination, generation, and retrieval of such dedicated position data involve not only processing and energy resources on the mobile terminal side, but also communication and processing resources on the network side. For example, satellite position signals have to be retrieved and processed on the mobile terminal, respective information has to be compiled and has to be sent over the network to the respective network entity for being incorporated and/or processed into/by the location database.
Moreover, the accuracy of position information retrieved from f satellite-based positioning systems is usually rather high and conventionally achieves position errors well below 10 meters. This accuracy is obtained as an inherent feature of satellite-based positioning systems, and a reduction of position information accuracy usually does not result in a substantial lowering of processing and/or network communication resources.
At the same time, however, network services that employ location information of mobile terminals may not require such high accuracy position information and may not at all make use of this high precision information. For example, the determination of whether a certain mobile terminal is to receive a location based network service or not, or what specific location based network service is to be provided to the mobile terminal may only require coarse information on the position of the mobile terminal. It may be fully sufficient to retrieve information on whether or not a certain mobile terminal is inside or outside a given geographical zone or area. An accuracy of such information reaching below several meters may be of now benefit to the provision and operation of the network service.
It is thus an object of the present invention to provide a network service to mobile terminals of a cellular telecommunications network that involves positional information of the mobile terminals and that reduces the amount of required processing and/or communication resources. This on both sides of the system, namely on the network side and on the mobile terminal side.